The present invention relates to renewable modified microelectrodes for electrochemical applications and to methods for making same.
Modified electrodes have become of great interest because of their ability to extend the range of characteristics provided by the intrinsic interfacial properties of traditional electrodes. Such electrodes have become important tools in electroanalytical chemistry and the uses have been expanding as new modifiers have been identified.
Heretofore, such electrodes have been prepared by application to the surface of an electrode a coating of a modifier to provide the desired alteration of the surface characteristics. In many applications, the surface layer becomes contaminated or attacked by the solution in which the electrode is immersed so that the modified electrode may not be reused. Moreover, the coating may not be uniform and thus produce variation in activity over the surface of the electrode.
Microelectrodes and ultramicroelectrodes are desirable for many analytical applications. Fabrication of microelectrodes with electroactive surfaces presents substantial problems. Moreover, such microelectrodes become contaminated and require frequent replacement
Thus, substitution of another microelectrode may involve some change in microelectrode characteristics and introduce problems of reproducibility of results.
It is an object of the present invention to provide a novel modified electrode which may be renewed by removing a surface portion thereof.
It is also an object to provide such a microelectrode which has substantially uniform characteristics along its length so that it may be renewed by removing end portions and provide substantially similar results.
A further object is to provide an electrode assembly which may combine therein microelectrodes having different types of modification.
Another object is to provide a novel method for preparing modified microelectrodes and for renewing such microelectrodes.